This invention relates to an improved optical telephone where an optical fiber is used as the transmission element.
In an optical telephone, it is required to convert amplitude modulated light to sound or mechanical energy. Most often, this is done by converting the modulated light into electrical energy and then amplifying and feeding it into an electromechanical transducer or earphone. In this invention, the modulated light is applied to an enclosed volume of gas. The volume and/or pressure of this gas varies in synchronism with the instantaneous energy or intensity of the modulated light. In this variation, the sounds are produced.
One of the difficulties encountered in an optical telephone where an optical fiber is used as the transmission element of modulated light is that optical energy is not uniformly transmitted into the enclosed volume of gas. This results in an inefficient conversion of the modulated light into sound.